A fairly typical form of band belt conveyor apparatus using for example a webbing belt or a rubber belt or a belt of like material includes at least one flexible band belt such as of webbing or rubber material which circulates endlessly between reversal stations and/or drive stations. The belt forms a load run and an idle run, with the belt being supported on support rollers at least in part between the above-indicated stations.
Band belt conveyor apparatuses of the above-indicated type are frequently used as bulk material conveyors in mining operations, for example in open cast mining works. The materials to be transported are conveyed on an endlessly circulating belt. The required pulling force to drive the belt is applied thereto in force-locking relationship at at least one of the reversal points or reversal stations of the belt. The belt is supported over support rollers between the reversal points or reversal stations. A distinction is frequently drawn between stationary belt installations and movable belt installations. Movable belt installations are frequently used for example in open cast mining operations in which the conveyor installations must advance with the progress of the mining location.
Problems with and troubles on band belts are primarily to be attributed to defective support rollers or support frame structures which are improperly oriented. Improperly oriented support structures cause the belt to run inclinedly in an off-track condition or give rise to overloading at individual belt support rollers. Bearing damage at the bearings of the belt support rollers are frequently the cause of problems and difficulties in that respect. That gives rise to an increased level of heat generation which in the worst-case scenario can lead to an open fire. Defective or damaged support rollers frequently make themselves noticed by virtue of elevated levels of sound emission or indeed only by the production of noise or by virtue of fire.
DE 10003308 A1 discloses a method and an apparatus for detecting and locating noise sources on conveyor belts, in particular on belt sections in open cast mining operations. The method is carried out by means of a mobile measuring device which is not fixedly linked to the conveyor belt and which is used while moving in approximately parallel relationship at a conveyor belt to detect the sound level emitted by the individual rollers and/or garland sections of the conveyor belt. The sound level which is continuously detected at least in portion-wise manner in relation to the belt during the advance movement is divided into a number of n-sound spectra and given sound spectra are associated with specific rollers or garland portions of the belt by means of a locating or positional signal which is recorded in parallel with the detected sound level.
Although that operating procedure has proven to be worthwhile nonetheless it relatively frequently happens that support rollers which are in a good condition are picked out for removal or replacement because the procedure does not provide absolute accuracy in terms of locating the support rollers. It can also be easily imagined that it is a comparatively arduous task to cover what may involve hundreds of kilometers on belt lines in that way.
Finally the orientation condition of belt installations is also an aspect of crucial significance in terms of energy consumption and trouble-free operation. If support roller frame structures are properly oriented it is possible to achieve a comparatively centrally aligned belt travel. If the quality of alignment is somewhat worse however it is no longer possible to guarantee that the belt travels in a central position but it is not possible to detect that improper orientation of the belt by way of the procedure involving detecting sound emission.
DE 199 11 642 A1 discloses a method of and an apparatus for diagnosing the damage condition of support rollers in band belt conveyors of a typical configuration as referred to hereinbefore, wherein thrust or transverse stress measuring sensors for central rollers and travel measuring sensors are arranged at the surface of or in the interior of the conveyor belt. The measurement values produced by the thrust or transverse stress measuring sensors for central rollers and the travel measuring sensors when the conveyor belt passes in an empty or loaded condition over the support rollers are used to calculate the peripheral force of the support rollers. That force is recorded, subjected to preliminary processing, put into intermediate storage and read out when passing an interrogation unit.
That operating procedure requires a separate travel measuring system to be integrated into the sensor arrangement. Furthermore calibration of the system is required, by way of a single load. In addition, the respective current weight of material being conveyed has to be ascertained using a volume or density scanner or a belt weighing arrangement.
DE 199 11 640 A1 discloses arranging pressure measuring sensors and travel measuring sensors at the surface of a conveyor belt or in the interior thereof. The measurement values from those sensors, when the empty conveyor belt passes over the support rollers of the assembly, are used to register any installation faults or defects in the support roller station at the upper run of the belt, so that such faults or defects can then be calculated. In addition pressure measuring sensors are arranged laterally of the conveyor belt and acceleration measuring sensors are arranged on the material side of the conveyor belt in such a way that on the basis of the measurement values thereof any installation faults or defects in respect of the support roller stations can be registered, calculated, stored and items of information can be produced therefrom relating to their condition and the need for repair or maintenance. It will be noted however that that method is also comparatively complicated and expensive.